She said it's okay, rub my head and told me to relax

The girl is not interested in his thoughts, so in a seductive way she carresses him and distracts him from it all so hopefully he will stop thinking about it, and start focusing on having sex with her — because that’s what she really wants.

Head is a double meaning for his penis head, and of course, his actual head. The two is a constant battle for J. Cole, because he wants to get in touch with her head, but she wants to get in touch with his other head.